The Precursors to leave a legacy - much large robots, which one rusts in the ground. They leave an enormous source of the energy ECO!!

Jak and Daxter live on a south island on the continent. They are two naughty boys that they never do what is said. They know that it is forbidden to going to the island of Misty but have ignored the warnings. Stealing a boat they direct over to the island and have explored.

On the island they have spied on two mysterious people, on a old man and one beautiful woman. They manage an army of horrible monsters. The old man wants to control of all the Eco and to make everyone its slave.

Jak and Daxter try to escape without being discovered, but when one of the monsters attacks them, Daxter is struck in an enormous bathtub of oily stuff - dark Eco! When he climbs outside has become a hairy orange rat!

Now Jak and Daxter must find aid. They must find the old wise person who can again give return to Daxter within a human being. But before that, they must try to stop the evil pair and its cowardly plan!